Employees are increasingly involved in internal corporate discussion processes, often via online platforms. On such platforms, diverse opinions converge and controversial discussions may unfold. Anonymity is assumed to encourage reticent users to speak their mind and to allow for the expression of divergent views, but it has also been found to affect how arguments are received, including perceptions of credibility and, thus, persuasiveness. This paper considers how user anonymity affects communication persuasiveness in online discussions with both identified and anonymous treatment conditions. Drawing upon the elaboration likelihood model of persuasion, we find that anonymity affects persuasiveness via the opposing paths of credibility and involvement.